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  1. #1
    Member
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    Feb 2013
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    Shipman, Illinois
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    Mercury 250 pro XB Throttle Plates

    Hello thanks in advance. My 250 Pro XB when the engine ia off and someone gives WOT the bottom throttle plate only opens 1/4-1/3. Or is at about a 45° angle and the top plate does not move at all. We have lost hole shot and can only get to about 5400 rpm. I was just wondering if this is normal for the throttle plates or if something is out of adjustment. Thank you

  2. Member
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    #2
    Also the throttle stop is a good 1/4" from touching the block.

  3. Member
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    Jul 2004
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    #3
    Something IS wrong check all the linkages and adjust if necessary.



  4. Member
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    Feb 2013
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    #4
    Ok thanks for the reply. I'm going to look into adjustments.

  5. Kllr bee
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    Jun 2004
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    Centerpoint, Alabama
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    #5
    Top and bottom butterflies should be horizontal at full throttle. Top should start opening at about half throttle. If not check cable and throttle linkage. If it has a hotfoot that could be problem.
    Richard

  6. Member
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    Feb 2013
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    Shipman, Illinois
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    #6
    Thank you it does have a hot foot and we were thinking that was the problem as we just spent a ton of money having new reeds and fuel system rebuilt. Injectors flow tested. I can't believe the mechanic didn't notice that. Will I have to adjust the TPS or anything when I get them both open like they should be?

  7. Major Flagelator Gamblinman's Avatar
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    Jun 2004
    Location
    Yantis, TX
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    4,121
    #7
    Quote Originally Posted by Rlueb View Post
    Thank you it does have a hot foot and we were thinking that was the problem as we just spent a ton of money having new reeds and fuel system rebuilt. Injectors flow tested. I can't believe the mechanic didn't notice that. Will I have to adjust the TPS or anything when I get them both open like they should be?

    Wouldn't hurt to check to make sure its within parameters.
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."

  8. Member
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    Jun 2013
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    LONGVIEW TEXAS
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    #8
    easily overlooked,have seen boats worked on by many only to find it was HF adjustment or or beer can stuck behind it
    .................................................. ...the scariest thing in life is the unknown ...................................

  9. Member
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    Feb 2013
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    Shipman, Illinois
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    #9
    Sure enough it was the hot foot was not allowing WOT. Worked on it this morning, took it for a short blast up the river and wow what a difference it hasn't had power like that in 10 years. I can't believe the mechanics both Merc Certified didn't check that. Thanks again for the help here.
    2002 Triton Tr-21 Merc 250 Pro XB OT430582

  10. Member
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    Nov 2016
    Location
    Danvillle, CA
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    #10
    In mercury land it is a jungle out there. U have to get involved or bad things happens like costly not required repairs or the opposite in my case. I went against recommendations and replaced a air compressor only to find out that I was right as the compressor was shot and it was about to blow.